Problem: Simplify the following expression: $k = \dfrac{2h^2}{3fh + h} - \dfrac{4gh}{3fh + h}$ You can assume $f,g,h \neq 0$.
Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{2h^2 - (4gh)}{3fh + h}$ $k = \dfrac{2h^2 - 4gh}{3fh + h}$ The numerator and denominator have a common factor of $h$, so we can simplify $k = \dfrac{2h - 4g}{3f + 1}$